Slider and clam shell (i.e. folding), as well as other types of devices having multiple housings which move relative to one another, represent a form factor, which has enjoyed a degree of customer acceptance. At least one of the advantages associated with devices having a two part housing, is the ability of the device to be reconfigured dependent upon the current mode of operation. In a device having a slider configuration, the two housing portions will generally shift laterally relative to one another, with the two housing portions typically traveling along respective paths, that are generally parallel to one another. In a device having a clam-shell configuration, the two housing portions will generally rotate relative to one another about a hinged connection. The slider, the clam-shell as well as other multiple housing configurations enable form factors, can generally be more compact when not in use, which can allow the same to be stored more readily, where the two housing portions are allowed to more substantially overlap or nest. Alternatively, when in use, the two housing portions move apart or expand to provide a device with greater surface area to simultaneously support a larger exposed keypad and display, and/or to provide greater length or distance between the microphone and speaker to better bridge the gap defined by the distance between the user's mouth and the user's ear.
However because the components which support processing of signals and/or the supply of power are each often limited to one of the two housing portions, while elements which need to receive power or need to access the processing capabilities of the device are spread across both of the housing portions, the conveyance of power or signals between the two housing portions need to be supported. Power supplying devices, such as batteries, are commonly positioned within a base portion of the device. In the same or other instances, the primary processing element, such as a microprocessor, may be similarly located in one of the two housing portions, such as the base portion, and may need to communicate with elements located in one or both of the two housing portions including instances in which a communication connection with an element in the other housing portion is desired. The base portion also commonly includes the keypad, communication circuitry, and the microphone. The flip or slider portion often includes a display and a speaker, as well as sometimes a camera. It is further envisioned that the flip or slider portion may also increasingly incorporate biometric sensors, such as a fingerprint sensor. In order to support the increasing number of electrical elements, as well as elements having larger size and increasing resolution (i.e. displays and/or cameras) in a multiple housing element device, such as a clamshell or a slider type configuration form factor, communication connections between the multiple housings that support a larger number of signals and/or higher data rates are becoming increasingly important. Both of which are complicated by the need for the signals to be routed through the coupling element, such as a hinge element or a slider mechanism, which couples the multiple housing elements together.
Increases in the amount of data being communicated in an existing number of communication connections will often involve data signals having higher data rates, which can result in a corresponding increase in the amount of electromagnetic energy often characterized as noise and interference, in the case where the electrical signals are conveyed by one or more electrical conductors. In some instances, it may be possible to provide at least some electromagnetic shielding to help alleviate and/or address the production of any unwanted noise or interference. However, in the case where the signals are being routed though a coupling element which supports the relative movement of multiple housing portions, attempting to account for any increases in electromagnetic noise and interference may be problematic, as there can be difficulties associated with providing suitable electromagnetic shielding.
Traditionally, communications between housing portions in at least some instances have been supported using a flexible circuit, which contains one or more signaling paths. Opposite ends of the flexible circuit are generally coupled to respective ones of the two housings, and the length of the flexible circuit is often allowed to include one or more overlapping folds that include one or more bends to selectively create a varying amount of unrealized length, which can accommodate relative movement of the two ends between positions where the two ends are alternatively closer and farther apart as the two housings move relative to one another. In order to accommodate a bend in the flexible circuit, the various layers are sometimes separated. The separation of any shield layers relative to the layers containing signal conveying conductors will often impact the effectiveness of the shield layers proximate the point of any separation. Furthermore the use of a flexible circuit for purposes of conveying electrical signals and the corresponding provision for overlapping folds to account for the movement between housing portions and corresponding communication endpoints, contributes to a requirement for an often meaningful amount of space or volume to accommodate the communication pathways, where space or volume may be at a premium in devices where overall reductions in size are typically strongly desired.
In at least some instance the optical conveyance of one or more signals can sometimes help to alleviate the potential for noise or interference. However, a purely optical solution is not always possible as it is very inefficient to convey power optically. Consequently, the present inventors have recognized that electromagnetic noise and interference, which continues to be present even with the use of differential signaling, can be largely avoided by optically conveying the data signals, as opposed to electrically conveying the same. Further, the inventors have recognized that it is further beneficial to maintain an ability to continue to provide an electrically conductive path for the routing of some signals in addition to the optically conductive paths. As a result, a circuit substrate, which supports both optically and electrically conveyed signals would be beneficial.